Realization of polarization-invariant energy modulation in high-order radially polarized cylindrical vector beams

Here, an experimental approach is introduced to redistribute optical energy among the multiple concentric rings of high-order radially polarized R-TEM laser modes, differing from conventional high-order R-TEM modes that inherently exhibit non-uniform energy across their rings. By employing a diffractive optical element formed from a binary phase mask with two oppositely phased regions, the energy distribution among the rings can be tuned to achieve a variable intensity ratio in the ring pattern. Furthermore, the preserved orientation of the linear polarization vectors across the entire beam cross-section, together with the invariant Stokes parameter and Stokes phase under modulation, numerically confirms that the intrinsic polarization structure and modal identity of radially polarized beams remain unchanged throughout the process. The resulting modulated high-order R-TEM modes are expected to surpass standard R-TEM modes for applications that require ring structures with nearly equal intensities, such as particle manipulation, optical lithography, and optical data storage.